The invention relates to programming a radio telephone. Before a radio telephone bought off-the-shelf is fully functional it is necessary for the purchaser to sign up with a service provider. Although a telephone is manufactured with a unique Electronic Serial Number ESN, in order to connect to a radio telephone system of the purchasers choice (eg Cellnet or Vodaphone in the UK), the radio telephone must be provided with sufficient information to identify the radio telephone user and the system to which it is connected. This information is provided in the Number Assignment Module (NAM) information.
The NAM information includes a Mobile Identification Number (MIN) and data indicating the service provider chosen. In addition to this information relating to the specific radio telephone and service provider, the NAM includes security data used during registration to confirm the identity of the radio telephone and data providing details of a `Home Traffic Area` and `System Control Channels`. The details of the `System Control Channels` may include information relating to the level of service requested such as an access overload class providing information relating to the relative priority given to calls made by the specific subscriber. The radio telephone uses all this NAM information along with its ESN to gain access to the chosen radio telephone system.
A person buying a radio telephone expects to leave the store with a telephone ready for use. It is therefore necessary or, at the very least, highly desirable for the NAM information to be entered at the point of sale. This is currently achieved by a sales assistant programming the relevant data into a telephone. The data is obtained from the chosen service provider by telephone and is usually entered through the key pad of the radio telephone. This method of data entry has a number of drawbacks. It is slow as the sales assistant must ring the service provider, request the relevant data, write it down, and finally laboriously enter it via the radio telephone keypad. It is open to error as the assistant may write down or enter the data incorrectly. It is relatively insecure as the data can be intercepted and vital programming codes are known at the point of sale, and the process is complicated. Sales assistants dealing with a variety of products and perhaps selling only one telephone every few days will have to be constantly reminded of how to programme the information into the telephone with the attendant possibilities of error. One consequence of all this is that the purchaser may have to return to the retailer a few hours after the purchase is completed to collect the fully operational telephone. This is clearly not desirable.
In some stores the NAM information is programmed into the radio telephone using a computer. Instead of directly entering the data via the keypad of the radio telephone the sales assistant enters the relevant information via a computer keyboard. An interface box is used to link the telephone to the computer and to provide the necessary level of security. This provides an advantage over the manual system in that the information is seen on the computer screen prior to entry so that mistakes in keying-in can be corrected more easily. In addition the interface box holds the security information so it is not known at the point of sale. It also has the advantage that, as much of the programmed information will be common to all radio telephone subscribers only the unique identification information and those unusual requirements chosen by the purchaser need actually to be keyed-in. This reduces the chances of error and speeds up the process. In essence, however, this method is merely the computerization of the manual system discussed above.
Although programming via computer provides some advantages over the manual process it is an expensive way of providing a relatively small improvement in efficiency and security. Not all retail outlets have a convenient computer and the dedicated interface box is an additional unwelcome expense. As a consequence this system is not often used.